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Sirius is gradually moving closer to the Solar System and it is expected to increase in brightness slightly over the next 60,000 years to reach a peak magnitude of −1.68. Coincidentally, at about the same time, Sirius will take its turn as the southern Pole Star, around the year 66,270 AD.
The second brightest is Sirius at −1.46 mag. ... Venus −4.92 mag; Jupiter −2.94 mag; ... Single magnitude values quoted for variable stars come from a variety ...
For example, a magnitude 2.0 star is 2.512 times as bright as a magnitude 3.0 star, 6.31 times as magnitude 4.0, and 100 times magnitude 7.0. The brightest astronomical objects have negative apparent magnitudes: for example, Venus at −4.2 or Sirius at −1.46.
A more complex definition of absolute magnitude is used for planets and small Solar System bodies, based on its brightness at one astronomical unit from the observer and the Sun. The Sun has an apparent magnitude of −27 and Sirius, the brightest visible star in the night sky, −1.46. Venus at its brightest is -5.
For comparison, Sirius has an absolute magnitude of only 1.4, which is still brighter than the Sun, whose absolute visual magnitude is 4.83. The Sun's absolute bolometric magnitude is set arbitrarily, usually at 4.75. [4] [5] Absolute magnitudes of stars generally range from approximately −10 to +20. The absolute magnitudes of galaxies can be ...
Many brown dwarfs are not listed by visual magnitude but are listed by near-infrared J band apparent magnitude due to how dim (and often invisible) they are in visible color bands (U, B or V). Absolute magnitude (with electromagnetic wave, 'light' band denoted in subscript) is a measurement at a 10-parsec distance across imaginary empty space ...
The angular diameter of the Sun, as seen from Earth, is about 250,000 times that of Sirius. (Sirius has twice the diameter and its distance is 500,000 times as much; the Sun is 10 10 times as bright, corresponding to an angular diameter ratio of 10 5, so Sirius is roughly 6 times as bright per unit solid angle.)
An observer aloft in Venus's cloud tops, on the other hand, would circumnavigate the planet in about four Earth days and see a sky in which Earth and the Moon shine brightly (about magnitudes −6.6 [5] and −2.7, respectively) at opposition. The maximum angular separation between the Moon and Earth from the perspective of Venus is 0.612°, or ...